Reverse order of migrations

src/gui/application.cpp

@@ -72,11 +72,15 @@ void migrateConfigFile(const QCoreApplication *app)
 {
     using namespace OCC;
 
+    static const auto logPrefix = QStringLiteral("Settings migration: ");
+
     if (!ConfigFile::exists()) {
         // check whether an old config location must be migrated
         // we support multiple locations from old versions
         // these are worked on in-order to upgrade from version to version
         // the algorithm is the same for all these locations, thus we can use a loop
+        // note that we try to migrate in descending order, i.e., we try to migrate from the last release, then from the release before, ...
+        // this is done in order to avoid porting old configu
         QStringList configLocationsToMigrate;
 
         {
@@ -89,47 +93,62 @@ void migrateConfigFile(const QCoreApplication *app)
 
             QCoreApplication::setApplicationName(Theme::instance()->appNameGUI());
 
+            // location used in versions from 2.5 to 2.8
+            configLocationsToMigrate.append(QStandardPaths::writableLocation(Utility::isWindows() ? QStandardPaths::AppDataLocation : QStandardPaths::AppConfigLocation));
+
             // location used in versions <= 2.4
             // We need to use the deprecated QDesktopServices::storageLocation because of its Qt4 behavior of adding "data" to the path
             configLocationsToMigrate.append(QDesktopServices::storageLocation(QDesktopServices::DataLocation));
-
-            // location used in versions from 2.5 to 2.8
-            configLocationsToMigrate.append(QStandardPaths::writableLocation(Utility::isWindows() ? QStandardPaths::AppDataLocation : QStandardPaths::AppConfigLocation));
         }
 
-
         for (auto oldDir : configLocationsToMigrate) {
+            // prove me wrong!
+            bool success = false;
+
             if (oldDir.endsWith('/')) {
                 // macOS 10.11.x does not like trailing slash for rename/move.
                 oldDir.chop(1);
             }
 
             if (QFileInfo(oldDir).isDir()) {
                 auto confDir = ConfigFile::configPath();
-                if (confDir.endsWith('/'))
-                    confDir.chop(1); // macOS 10.11.x does not like trailing slash for rename/move.
-                qCInfo(lcApplication) << "Migrating old config from" << oldDir << "to" << confDir;
+
+                if (confDir.endsWith('/')) {
+                    // macOS 10.11.x does not like trailing slash for rename/move.
+                    confDir.chop(1);
+                }
+
+                qCInfo(lcApplication) << logPrefix << "Migrating old config from" << oldDir << "to" << confDir;
 
                 if (!QFile::rename(oldDir, confDir)) {
-                    qCWarning(lcApplication) << "Failed to move the old config directory to its new location (" << oldDir << "to" << confDir << ")";
+                    qCWarning(lcApplication) << logPrefix << "Failed to move the old config directory to its new location (" << oldDir << "to" << confDir << ")";
 
                     // Try to move the files one by one
                     if (QFileInfo(confDir).isDir() || QDir().mkpath(confDir)) {
                         const auto filesList = QDir(oldDir).entryInfoList(QDir::Files);
-                        qCInfo(lcApplication) << "Will move the individual files" << filesList;
+                        qCInfo(lcApplication) << logPrefix << "Will move the individual files" << filesList;
                         for (const auto &fileInfo : filesList) {
                             if (!QFile::rename(fileInfo.canonicalFilePath(), confDir + "/" + fileInfo.fileName())) {
-                                qCWarning(lcApplication) << "Fallback move of " << fileInfo.fileName() << "also failed";
+                                qCWarning(lcApplication) << logPrefix << "Fallback move of " << fileInfo.fileName() << "also failed";
                             }
                         }
                     }
                 } else {
+                    // migration worked!
+                    success = true;
+
 #ifndef Q_OS_WIN
                     // Create a symbolic link so a downgrade of the client would still find the config.
                     QFile::link(confDir, oldDir);
 #endif
                 }
             }
+
+            if (success) {
+                // we found a suitable config directory to migrate, hence we can stop here
+                // if we continued to run, we would try to overwrite the working migration
+                break;
+            }
         }
     }
 }